/* atktopbm.c - convert Andrew Toolkit raster object to portable bitmap
**
** Copyright (C) 1991 by Bill Janssen
**
** Permission to use, copy, modify, and distribute this software and its
** documentation for any purpose and without fee is hereby granted, provided
** that the above copyright notice appear in all copies and that both that
** copyright notice and this permission notice appear in supporting
** documentation.  This software is provided "as is" without express or
** implied warranty.
*/

#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#include "pbm.h"


/* readatkraster
**
** Routine for reading rasters in .raster form.  (BE2 rasters version 2.)
*/

/* codes for data stream */
#define WHITEZERO   'f'
#define WHITETWENTY 'z'
#define BLACKZERO   'F'
#define BLACKTWENTY 'Z'
#define OTHERZERO   0x1F

#define WHITEBYTE   0x00
#define BLACKBYTE   0xFF

/* error codes (copied from $ANDREW/atk/basics/common/dataobj.ch) */
/* return values from Read */
#define dataobject_NOREADERROR  0
#define dataobject_PREMATUREEOF 1
#define dataobject_NOTBE2DATASTREAM 2 /* backward compatibility */
#define dataobject_NOTATKDATASTREAM 2 /* preferred version */
#define dataobject_MISSINGENDDATAMARKER 3
#define dataobject_OBJECTCREATIONFAILED 4
#define dataobject_BADFORMAT 5

/* ReadRow(file, row, length) 
** Reads from 'file' the encoding of bytes to fill in 'row'.  Row will be
** truncated or padded (with WHITE) to exactly 'length' bytes.
**
** Returns the code that terminated the row.  This may be
**      '|'     correct end of line
**      '\0'    if the length was satisfied (before a terminator)
**      EOF     if the file ended
**      '\'  '{'    other recognized ends. 
** The '|' is the expected end and pads the row with WHITE.
** The '\' and '{' are error conditions and may indicate the
** beginning of some other portion of the data stream.
** If the terminator is '\' or '{', it is left at the front of the input.
** '|' is gobbled up.
*/

/* macros to generate case entries for switch statement */
#define case1(v) case v
#define case4(v) case v: case (v)+1: case (v)+2: case(v)+3
#define case6(v) case4(v): case ((v)+4): case ((v)+5)
#define case8(v) case4(v): case4((v)+4)

static long
ReadRow(FILE * const file, unsigned char * const row, long const length) {
/*----------------------------------------------------------------------------
  'file' is where to get them from.
  'row' is where to put bytes.
  'length' is how many bytes in row must be filled.
-----------------------------------------------------------------------------*/
    /* Each input character is processed by the central loop.  There are 
    ** some input codes which require two or three characters for
    ** completion; these are handled by advancing the state machine.
    ** Errors are not processed; instead the state machine is reset
    ** to the Ready state whenever a character unacceptable to the
    ** current state is read.
    */
    enum stateCode {
        Ready,      /* any input code is allowed */
        HexDigitPending,    /* have seen the first of a hex digit pair */
        RepeatPending,  /* repeat code has been seen:
                   must be followed by two hex digits */
        RepeatAndDigit};    /* have seen repeat code and its first
                   following digit */
    enum stateCode InputState;  /* current state */
    register int c;     /* the current input character */
    register long repeatcount = 0;  /* current repeat value */
    register long hexval;   /* current hex value */
    long pendinghex = 0;    /* the first of a pair of hex characters */
    int lengthRemaining;
    unsigned char * cursor;
    
    /* We cannot exit when length becomes zero because we need to check 
    ** to see if a row ending character follows.  Thus length is checked
    ** only when we get a data generating byte.  If length then is
    ** zero, we ungetc the byte.
    */

    lengthRemaining = length;
    cursor = row;

    InputState = Ready;
    while ((c=getc(file)) != EOF) switch (c) {

    case8(0x0):
    case8(0x8):
    case8(0x10):
    case8(0x18):
    case1(' '):
        /* control characters and space are legal and ignored */
        break;
    case1(0x40):    /* '@' */
    case1(0x5B):    /* '[' */
    case4(0x5D):    /*  ']'  '^'  '_'  '`' */
    case4(0x7D):    /* '}'  '~'  DEL  0x80 */
    default:        /* all above 0x80 */
        /* error code:  Ignored at present.  Reset InputState. */
        InputState = Ready;
        break;

    case1(0x7B):    /* '{' */
    case1(0x5C):    /* '\\' */
        /* illegal end of line:  exit anyway */
        ungetc(c, file);    /* retain terminator in stream */
        /* DROP THROUGH */
    case1(0x7C):    /* '|' */
        /* legal end of row: may have to pad  */
        while (lengthRemaining-- > 0)
            *cursor++ = WHITEBYTE;
        return c;
    
    case1(0x21):
    case6(0x22):
    case8(0x28):
        /* punctuation characters: repeat byte given by two
        ** succeeding hex chars
        */
        if (lengthRemaining <= 0) {
            ungetc(c, file);
            return('\0');
        }
        repeatcount = c - OTHERZERO;
        InputState = RepeatPending;
        break;

    case8(0x30):
    case8(0x38):
        /* digit (or following punctuation)  -  hex digit */
        hexval = c - 0x30;
        goto hexdigit;
    case6(0x41):
        /* A ... F    -  hex digit */
        hexval = c - (0x41 - 0xA);
        goto hexdigit;
    case6(0x61):
        /* a ... f  - hex digit */
        hexval = c - (0x61 - 0xA);
        goto hexdigit;

    case8(0x67):
    case8(0x6F):
    case4(0x77):
        /* g ... z   -   multiple WHITE bytes */
        if (lengthRemaining <= 0) {
            ungetc(c, file);
            return('\0');
        }
        repeatcount = c - WHITEZERO;
        hexval = WHITEBYTE;
        goto store;
    case8(0x47):
    case8(0x4F):
    case4(0x57):
        /* G ... Z   -   multiple BLACK bytes */
        if (lengthRemaining <= 0) {
            ungetc(c, file);
            return('\0');
        }
        repeatcount = c - BLACKZERO;
        hexval = BLACKBYTE;
        goto store;

hexdigit:
        /* process a hex digit.  Use InputState to determine
            what to do with it. */
        if (lengthRemaining <= 0) {
            ungetc(c, file);
            return('\0');
        }
        switch(InputState) {
        case Ready:
            InputState = HexDigitPending;
            pendinghex = hexval << 4;
            break;
        case HexDigitPending:
            hexval |= pendinghex;
            repeatcount = 1;
            goto store;
        case RepeatPending:
            InputState = RepeatAndDigit;
            pendinghex = hexval << 4;
            break;
        case RepeatAndDigit:
            hexval |= pendinghex;
            goto store;
        }
        break;

store:
        /* generate byte(s) into the output row 
            Use repeatcount, depending on state.  */
        if (lengthRemaining < repeatcount) 
            /* reduce repeat count if it would exceed
                available space */
            repeatcount = lengthRemaining;
        lengthRemaining -= repeatcount;  /* do this before repeatcount-- */
        while (repeatcount-- > 0)
                *cursor++ = hexval;
        InputState = Ready;
        break;

    } /* end of while( - )switch( - ) */
    return EOF;
}



#undef case1
#undef case4
#undef case6
#undef case8



static void
ReadATKRaster(FILE * const file, 
              int * const rwidth, 
              int * const rheight, 
              unsigned char ** const destaddr) {

    register long row, rowlen;  /* count rows;  byte length of row */
    int version;
    char keyword[6];
    int discardid;
    int objectid;     /* id read for the incoming pixel image */
    long tc;            /* temp */
    int width, height;      /* dimensions of image */

    if (fscanf(file, "\\begindata{raster,%d", &discardid) != 1
                || getc(file) != '}' || getc(file) != '\n')
      pm_error ("input file not Andrew raster object");

    fscanf(file, " %d ", &version);
    if (version < 2) 
      pm_error ("version too old to parse");

    {
        unsigned int options;
        long xscale, yscale;
        long xoffset, yoffset, subwidth, subheight;
        /* ignore all these features: */
        fscanf(file, " %u %ld %ld %ld %ld %ld %ld",  
               &options, &xscale, &yscale, &xoffset, 
               &yoffset, &subwidth, &subheight);
    }
    /* scan to end of line in case this is actually something beyond V2 */
    while (((tc=getc(file)) != '\n') && (tc != '\\') && (tc != EOF)) {}

    /* read the keyword */
    fscanf(file, " %5s", keyword);
    if (strcmp(keyword, "bits") != 0)
      pm_error ("keyword is not bits!");

    fscanf(file, " %d %d %d ", &objectid, &width, &height);

    if (width < 1 || height < 1 || width > 1000000 || height > 1000000) 
      pm_error ("bad width or height");

    *rwidth = width;
    *rheight = height;
    rowlen = (width + 7) / 8;
    *destaddr = (unsigned char *) 
        malloc (sizeof(unsigned char) * height * rowlen);
    for (row = 0;   row < height;   row++)
      {
        long c;

        c = ReadRow(file, *destaddr + (row * rowlen), rowlen);
        if (c != '|')
          {
        if (c == EOF)
          pm_error ("premature EOF");
        else
          pm_error ("bad format");
        break;
          }
      }
    while (! feof(file) && getc(file) != '\\') {};  /* scan for \enddata */
    if (fscanf(file, "enddata{raster,%d", &discardid) != 1
        || getc(file) != '}' || getc(file) != '\n')
      pm_error ("missing end-of-object marker");
}



int
main(int argc, char **argv) {

    FILE *ifp;
    register bit *bitrow, *bP;
    int rows, cols, row, col, charcount;
    unsigned char *data, mask;


    pbm_init ( &argc, argv );

    if ( argc > 2 )
        pm_usage( "[raster obj]" );
    
    if ( argc == 2 )
        ifp = pm_openr( argv[1] );
    else
        ifp = stdin;

    ReadATKRaster( ifp, &cols, &rows, &data );

    pm_close( ifp );

    pbm_writepbminit( stdout, cols, rows, 0 );
    bitrow = pbm_allocrow( cols );

    for ( row = 0; row < rows; ++row )
    {
        charcount = 0;
        mask = 0x80;
        for ( col = 0, bP = bitrow; col < cols; ++col, ++bP )
        {
            if ( charcount >= 8 )
            {
                ++data;
                charcount = 0;
                mask = 0x80;
            }
            *bP = ( *data & mask ) ? PBM_BLACK : PBM_WHITE;
            ++charcount;
            mask >>= 1;
        }
        ++data;
        pbm_writepbmrow( stdout, bitrow, cols, 0 );
    }

    pm_close( stdout );
    exit( 0 );
}

